Adult keeping a watchful eye over the nest site. Photo © eric Horstman

10 PsittaScene Summer 2014

The Pro-Bosque Foundation

has worked since 1993 to

protect and restore the

Cerro Blanco Protected

Forest, a reserve of nearly

15,000 acres of Ecuadorian

dry forest near the country’s

largest city, Guayaquil.

It was here in a small area

of the reserve that a drama

began to unfold with

one of the rarest macaws

in the world.

a GreaT Green Macaw nesT (A.a. guayaquilensis) was discovered in the Northwest part of the forest one early July. The nest was in the trunk of a dying Pigio tree (Cavanillesia platanifolia) in an area dominated by other trees of the same species. The open nest cavity was located about 65 feet from the ground in the smooth, grey trunk of the tree with its characteristic concentric rings. The bark of the Pigio tree is similar to balsa wood in consistency and previously Great Greens have been seen using their beaks and claws to excavate the nest cavities.

The male macaw would return to the nest tree three or four times a day to feed the female, who would briefly peek out of the top of the nest cavity to receive the regurgitated food.

On October 31st the chick’s head was first seen at the entrance and all seemed to point to an uneventful but ultimately successful nesting. The female began to

leave the chick for extended periods of time accompanying the male in the search for food.

However, during the entire nesting period, a series of incidents occurred with a number of nesting birds of prey. From July 10th to August 23rd a pair of Grey Hawks (Buteo nitidus) nested in a large Pigio about 130 feet from the macaws. The hawks would often fly near the macaw nest and even attacked the male macaw when it tried to return to the nest, delivering blows to its body. On the night of August 23rd an unknown predator attacked the nest and the hawks subsequently moved away from the area.

This was only the beginning of the skirmish with the macaws: starting on July 14th, a pair of Collared Forest-Falcons (Micrastur semitorquatus) was observed near the macaw nest. Things began to heat up when on August 6th the female falcon entered the macaw

Great Green Macaw © Steve Milpacher

By eric Horstman

TheRescue

Summer 2014 PsittaScene 11

Nest site in the trunk of a dying Pigio tree (Cavanillesia platanifolia) in the Cerro Blanco Protected Forest. Photo © eric Horstman

Macaw parents and juvenile making their way safely away from the nest site and the aggressive falcons. Photo © eric Horstman

The Collared Forest-Falcon is found in a range of tropical forested habitats from Central Mexico to Southern Brazil, and feeds on a variety of small mammals and birds. It is the largest species in the genus Micrastur. Photo © Alan Huett | Creative Commons 2.0

nest cavity, but was driven off by the male. From then on through the month of August the falcon attacks became more frequent, with the birds diving on the macaws and striking them with their beaks. They also would grapple with the macaws, clutching them in their talons and breaking off the attack as they fluttered towards the ground. By November 6th the forest falcons were preventing the macaws from approaching their nest and would pursue them sometimes more than 600 feet from the nest.

The juvenile macaw chick became desperate for food during two days of the falcon’s siege and was attacked more than twenty times at the entrance to the nest.

Finally, things came to a head when on November 8th the juvenile macaw was literally dragged from the nest by the pair of falcons. One of our researchers who was observing the macaws from a nearby blind rushed to the rescue of the fledgling as the two falcons attacked it at the base of the nest. Fortunately the macaw chick was unscathed and after a couple of days at my house being fed walnuts, papaya and other fruits, the chick was taken back up to the nest site.

The juvenile was placed back in the nest. In a scene right out of Hollywood, the parent birds flew over and the juvenile took off flying after them. The three macaws were seen flying together in the general area for several days afterwards. The forest falcons then quickly occupied the cavity for their own nest.

Eric Horstman is the Executive Director of Fundacion Pro-Bosque, Equador.

The Pro-Bosque Foundation (Fundacion Pro-Bosque) began its Guayaquil Macaw Conservation Program in 1993 and has continued until present. Their work has focused on locating and protecting active nest sites to prevent nest robbing of chicks for the national pet trade, protection of macaws and other wildlife species through anti-poaching patrols by park guards, and habitat restoration with native tree species used as both food and nesting trees for Great Green Macaws.